The present invention relates generally to information-transmitting devices (such as radio frequency identification, or “RFID”, tags), and more particularly, the use of such devices for detecting wear of items.
Information-transmitting devices, such as those commonly referred to as RFID tags, may be used for labeling and tracking items of merchandise from manufacturing through distribution and retail sale. A typical RFID tag includes both passive elements (e.g., an antenna) and active elements (e.g., a read-write data memory, control circuitry, and a radio frequency transponder). RFID transmissions are, by definition, wireless. RFID tags are typically not self-powered, but may receive their power via capacitative coupling from an external radio frequency source. When brought into proximity with an RFID reader at a typical effective distance of about 1 centimeter to 5 meters (depending on the type of tag), the RFID tag receives sufficient power to enable clocking the semiconductor and analog portions comprising the transponder, control circuits, and data memory through enough clock cycles that the tag can return the data bits from its memory as a digitally-encoded RF signal. This is advantageous because the tag can be read (or written) from a distance without the necessity of line-of-sight, as had been required to read a bar code with a laser scanner.
RFID technology has generally been utilized for inventory control (e.g., in a warehouse, manufacturing, or distribution facility) and for item identification at the point of sale as an improvement over today's nearly ubiquitous laser-scanned bar codes. Several large retailers have indicated a desire to begin using RFID tagging on all their inventory. The cost of RFID tags is expected to decline to the point of being cost-effective even on small-value retail items.